US.params <- list(admin = "US", # state or country
                  # q = 1, # Detection probability
                  # a = 0.346, # Proportion of cases that are asymptomatic # not used
                  # c = 1, # Transmissability of undetectable cases
                  # https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf
                  CFR = .009, 
                  # effective.infectious.period = list(dist="exponential", mean=2.67), # our analysis, not used
                  infectious.period = list(dist="exponential", mean=7), # accepted value
                  incubation.period = list(dist="gamma", mean=7.67, shape=4.1775942), # out analysis of US data
                  # from US data (our analysis) (not used)
                  report.to.death.period = list(dist="skewnormal", mean = 0.6123151, sd = 3.1429762,
                                                location = -2.388990, 
                                                scale = -2.388990, 
                                                shape = 1.728359),
                  # from China data: lognormal distribution with a 
                  # location parameter of 2.84 and a scale parameter of 0.52 
                  # (Jung et al.) https://doi.org/10.3390/jcm9020523 
                  onset.to.death.period = list(dist="lognormal", mean = 19.9, sd = 11.4)
                  )

Nowcast (outbreak size) = E + I = the number of non-isolated infected individuals